SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55294219f968547411787e3e8faadf670ffc9788f228a8bc4bf7b3b5db11b383' 
  AND token = 'yLz0GADxyH3t4Jyn/oDG+AKL75iNHiRkYfYW8TOwBXA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}